Most modern weapons are orders of magnitude more complex than WWII weapons. Many modern weapons are produced on specialized machinery that is in limited supply. For several weapons, we couldn't substancially increase the production rate over what we've been building for the past several years because the assembly plants have been geared for a lower rate of production.

This is nothing new. I remember reading an article in the early 1980s about how limited our manufacturing was for certain weapons. The article cited a particular critical part on the A-10, I think it was the wing spar, that could only be produced on a very specialized machine tool. There was exactly one of those tools available in the entire US and it was running full speed to produce parts for A-10s and other aircraft. Remember, the A-10 is the least complicated combat aircraft in the US inventory. Imagine the difficulty in trying to double production of more complex aircraft like the F-15E Strike Eagle.

The shift to a wartime production economy began in 1940 and really didn't hit full speed until 1943 or 44. Virtually all of American industry was turned to war production - steel mills, shipyards, automotive plants, etc. You couldn't buy a new car in 1943 for any amount of money. We have not done anything remotely resembling that kind of shift in production today. About all we've done is put on some extra shifts at certain select plants, such as those that produce smart bombs.